This Contemporary computer systems are multiprocessor or multicomputer machines. Their efficiency depends on good methods of administering the executed works. Fast processing of a parallel application is possible only when its parts are appropriately ordered in time and space. This calls for efficient scheduling policies in parallel computer systems. In this work deterministic problems of scheduling are considered. The classical scheduling theory assumed that the application in any moment of...

Topics: Load Scheduling, SISD, MIMD, MISD, SIMD, Communication Overhead, Computer Architecture

This Contemporary computer systems are multiprocessor or multicomputer machines. Their efficiency depends on good methods of administering the executed works. Fast processing of a parallel application is possible only when its parts are appropriately ordered in time and space. This calls for efficient scheduling policies in parallel computer systems. In this work deterministic problems of scheduling are considered. The classical scheduling theory assumed that the application in any moment of...

Topics: Load Scheduling, SISD, MIMD, MISD, SIMD, Communication Overhead, Computer Architecture

This Contemporary computer systems are multiprocessor or multicomputer machines. Their efficiency depends on good methods of administering the executed works. Fast processing of a parallel application is possible only when its parts are appropriately ordered in time and space. This calls for efficient scheduling policies in parallel computer systems. In this work deterministic problems of scheduling are considered. The classical scheduling theory assumed that the application in any moment of...

Topics: Load Scheduling, SISD, MIMD, MISD, SIMD, Communication Overhead, Computer Architecture

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Jul 25, 2010
07/10

by
Phillips, Edward P

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An experimental Round Robin on the measurement of the opening load in fatigue crack growth tests was conducted on Crack Closure Measurement and Analysis. The Round Robin evaluated the current level of consistency of opening load measurements among laboratories and to identify causes for observed inconsistency. Eleven laboratories participated in the testing of compact and middle-crack specimens. Opening-load measurements were made for crack growth at two stress-intensity factor levels, three...

Topics: PARALLEL PROGRAMMING, SIMD (COMPUTERS), COMPUTER SYSTEMS PERFORMANCE, COMPUTER SYSTEMS PROGRAMS,...

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Jul 26, 2010
07/10

by
Fralick, Gustave C.; Decker, Arthur J.; Blue, James W

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An experiment was performed to look for evidence of deuterium fusion in palladium. The experiment, which involved introducing deuterium into the palladium filter of a hydrogen purifier, was designed to detect neutrons produced in the reaction D-2 D-2 yields He-3 n as well as heat production. The neutron counts for deuterium did not differ significantly from background or from the counts for a hydrogen control. Heat production was detected when deuterium, but not hydrogen, was pumped from the...

Topics: CONFERENCES, MIMD (COMPUTERS), PARALLEL PROCESSING (COMPUTERS), SIMD (COMPUTERS), CHARGED...

Sorting has long been used to organize data in preparation for further computation, but sort computation allows some types of computation to be performed during the sort. Sort aggregation and sort distribution are the two basic forms of sort computation. Sort aggregation generates an accumulative or aggregate result for each group of records and places this result in one of the records. An aggregate operation can be any operation that is both associative and commutative, i.e., any operation...

Topics: NASA Technical Reports Server (NTRS), CLASSIFYING, DATA PROCESSING, PARALLEL PROCESSING...

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260

May 22, 2011
05/11

by
Glassman, Arthur J.; Lavelle, Thomas M

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Modifications made to the axial-flow compressor conceptual design code CSPAN are documented in this report. Endwall blockage and stall margin predictions were added. The loss-coefficient model was upgraded. Default correlations for rotor and stator solidity and aspect-ratio inputs and for stator-exit tangential velocity inputs were included in the code along with defaults for aerodynamic design limits. A complete description of input and output along with sample cases are included.

Topics: APPLICATIONS PROGRAMS (COMPUTERS), LAYOUTS, MIMD (COMPUTERS), SIMD (COMPUTERS), ARCHITECTURE...

Single instruction, multiple data (SIMD) computers consist of a very large number of processors executing a common sequence of instructions. Maintaining the full speedup potential of such machines is most sensitive to conditional execution in their programs, regions of code where some processing elements (PEs) perform no useful work. Techniques are presented for efficiently implementing nested conditional statements, specifically if and case statements, in SIMD machines, while adding minimal...

Topics: NASA Technical Reports Server (NTRS), PARALLEL PROGRAMMING, SIMD (COMPUTERS), COMPUTER SYSTEMS...

A compact scheme is a discretization scheme that is advantageous in obtaining highly accurate solutions. However, the resulting systems from compact schemes are tridiagonal systems that are difficult to solve efficiently on parallel computers. Considering the almost symmetric Toeplitz structure, a parallel algorithm, simple parallel prefix (SPP), is proposed. The SPP algorithm requires less memory than the conventional LU decomposition and is highly efficient on parallel machines. It consists...

Topics: NASA Technical Reports Server (NTRS), ALGORITHMS, FINITE DIFFERENCE THEORY, MATRICES (MATHEMATICS),...

High performance FORTRAN is a set of extensions for FORTRAN 90 designed to allow specification of data parallel algorithms. The programmer annotates the program with distribution directives to specify the desired layout of data. The underlying programming model provides a global name space and a single thread of control. Explicitly parallel constructs allow the expression of fairly controlled forms of parallelism in particular data parallelism. Thus the code is specified in a high level...

Topics: NASA Technical Reports Server (NTRS), APPLICATIONS PROGRAMS (COMPUTERS), ARCHITECTURE (COMPUTERS),...

Many problems can be described in terms of directed graphs that contain a large number of vertices where simple computations occur using data from adjacent vertices. A method is given for parallelizing such problems on an SIMD machine model that uses only nearest neighbor connections for communication, and has no facility for local indirect addressing. Each vertex of the graph will be assigned to a processor in the machine. Rules for a labeling are introduced that support the use of a simple...

Topics: NASA Technical Reports Server (NTRS), ARCHITECTURE (COMPUTERS), COMPUTER NETWORKS, GRAPH THEORY,...

A general approach to solve boundary value problems numerically in a parallel environment is discussed. The basic algorithm consists of two steps: the local step where all the P available processors work in parallel, and the global step where one processor solves a tridiagonal linear system of the order P. The main advantages of this approach are two fold. First, this suggested approach is very flexible, especially in the local step and thus the algorithm can be used with any number of...

Topics: NASA Technical Reports Server (NTRS), ALGORITHMS, BOUNDARY VALUE PROBLEMS, CENTRAL PROCESSING...

In numerical simulations of disordered electronic systems, one of the most common approaches is to diagonalize random Hamiltonian matrices and to study the eigenvalues and eigenfunctions of a single electron in the presence of a random potential. An effort to implement a matrix diagonalization routine for real symmetric dense matrices on massively parallel SIMD computers, the Maspar MP-1 and MP-2 systems, is described. Results of numerical tests and timings are also presented.

Topics: NASA Technical Reports Server (NTRS), MASSIVELY PARALLEL PROCESSORS, MATRICES (MATHEMATICS),...

Neural networks are a very useful tool for analyzing and modeling complex real world systems. Applying neural network simulations to real world problems generally involves large amounts of data and massive amounts of computation. To efficiently handle the computational requirements of large problems, we have implemented at Los Alamos a highly efficient neural network compiler for serial computers, vector computers, vector parallel computers, and fine grain SIMD computers such as the CM-2...

Topics: NASA Technical Reports Server (NTRS), CONNECTION MACHINE, MASSIVELY PARALLEL PROCESSORS, NEURAL...

Described here is how researchers implemented a scan line graphics generation algorithm on the Massively Parallel Processor (MPP). Pixels are computed in parallel and their results are applied to the Z buffer in large groups. To perform pixel value calculations, facilitate load balancing across the processors and apply the results to the Z buffer efficiently in parallel requires special virtual routing (sort computation) techniques developed by the author especially for use on...

Topics: NASA Technical Reports Server (NTRS), CENTRAL PROCESSING UNITS, COMPUTER GRAPHICS, MASSIVELY...

The goal of the research described is to develop flexible language constructs for writing large data parallel numerical programs for distributed memory (MIMD) multiprocessors. Previously, several models have been developed to support synchronization and communication. Models for global synchronization include SIMD (Single Instruction Multiple Data), SPMD (Single Program Multiple Data), and sequential programs annotated with data distribution statements. The two primary models for communication...

Topics: NASA Technical Reports Server (NTRS), DISTRIBUTED PROCESSING, MEMORY (COMPUTERS), MIMD (COMPUTERS),...

There are many problems which can be described in terms of directed graphs that contain a large number of vertices where simple computations occur using data from connecting vertices. A method is given for parallelizing such problems on an SIMD machine model that is bit-serial and uses only nearest neighbor connections for communication. Each vertex of the graph will be assigned to a processor in the machine. Algorithms are given that will be used to implement movement of data along the arcs of...

Topics: NASA Technical Reports Server (NTRS), ALGORITHMS, ARCHITECTURE (COMPUTERS), GRAPH THEORY, PARALLEL...

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405

May 23, 2011
05/11

by
Ackerman, Andrew S.; Toon, Owen B.; Hobbs, Peter V

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A detailed 1D model of the stratocumulus-topped marine boundary layer is described. The model has three coupled components: a microphysics module that resolves the size distributions of aerosols and cloud droplets, a turbulence module that treats vertical mixing between layers, and a multiple wavelength radiative transfer module that calculates radiative heating rates and cloud optical properties. The results of a 12-h model simulation reproduce reasonably well the bulk thermodynamics,...

Topics: CMOS, RANDOM ACCESS MEMORY, DECODERS, LAYOUTS, SIMD (COMPUTERS), COMPUTER DESIGN, MULTIPROCESSING...

Neural networks have attracted much interest recently, and using parallel architectures to simulate neural networks is a natural and necessary application. The SIMD model of parallel computation is chosen, because systems of this type can be built with large numbers of processing elements. However, such systems are not naturally suited to generalized communication. A method is proposed that allows an implementation of neural network connections on massively parallel SIMD architectures. The key...

Topics: NASA Technical Reports Server (NTRS), ALGORITHMS, ARCHITECTURE, NEURAL NETS, PARALLEL PROCESSING...

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May 22, 2011
05/11

by
Knacke, Roger F

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Infrared spectroscopy provides unique insights into the chemistry and dynamics of the atmospheres of Jupiter and Saturn -- and of Titan, the enigmatic satellite of Saturn. The 5 micron spectral region of these objects is transparent to deep levels, and is therefore particularly useful for the identification of molecules in the deep atmosphere at very low (parts per billion) concentrations. In 1991 we obtained data at J, H, K, and M and made repeated observations of Titan's albedo as the...

Topics: ARCHITECTURE (COMPUTERS), MATHEMATICAL MODELS, MEMORY (COMPUTERS), PERFORMANCE TESTS, RESPONSE TIME...

We have developed a tool to solve the radiative transfer equation for a three-dimensional astrophysical object on the SIMD computer MasPar MP-1. With this tool we can rapidly calculate the image of such an object as seen from an arbitrary direction and at an arbitrary wavelength. Such images and spectra can then be used to directly compare observations with the model. This tool can be applied to many different areas in astrophysics, e.g., HI disks of galaxies and polarized radiative transfer of...

Topics: NASA Technical Reports Server (NTRS), ACCRETION DISKS, DISK GALAXIES, MASSIVELY PARALLEL...

Architecture Adaptive Computing Environment (aCe) is a software system that includes a language, compiler, and run-time library for parallel computing. aCe was developed to enable programmers to write programs, more easily than was previously possible, for a variety of parallel computing architectures. Heretofore, it has been perceived to be difficult to write parallel programs for parallel computers and more difficult to port the programs to different parallel computing architectures. In...

Topics: NASA Technical Reports Server (NTRS), PARALLEL PROCESSING (COMPUTERS), ARCHITECTURE (COMPUTERS),...

Massive parallelism appears in three domains of action of concern to scientists, where it produces collective action that is not possible from any individual agent's behavior. In the domain of data parallelism, computers comprising very large numbers of processing agents, one for each data item in the result will be designed. These agents collectively can solve problems thousands of times faster than current supercomputers. In the domain of distributed parallelism, computations comprising large...

Topics: NASA Technical Reports Server (NTRS), ALGORITHMS, MIMD (COMPUTERS), NETWORK CONTROL, PARALLEL...

The Fast Fourier Transform (FFT) is a mainstay of certain numerical techniques for solving fluid dynamics problems. The Connection Machine CM-2 is the target for an investigation into the design of multidimensional Single Instruction Stream/Multiple Data (SIMD) parallel FFT algorithms for high performance. Critical algorithm design issues are discussed, necessary machine performance measurements are identified and made, and the performance of the developed FFT programs are measured. Fast...

Topics: NASA Technical Reports Server (NTRS), COMPUTER SYSTEMS PERFORMANCE, FAST FOURIER TRANSFORMATIONS,...

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May 23, 2011
05/11

by
Bansal, Narottam P.; Eldridge, Jeffrey I

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Unidirectional celsian matrix composites having approx. 42 volume percent of uncoated or BN/SiC-coated Hi-Nicalon fibers were tested in three-point bend at room temperature. The uncoated fiber-reinforced composites showed catastrophic failure with strength of 210 /- 35 MPa and a flat fracture surface. In contrast, composites reinforced with BN/SiC-coated fibers exhibited graceful failure with extensive fiber pullout. Values of first matrix cracking stress and strain were 435 /- 35 MPa and 0.27...

Topics: PARALLEL PROCESSING (COMPUTERS), ALGORITHMS, NAVIER-STOKES EQUATION, MEMORY (COMPUTERS), MASSIVELY...

A compact scheme is a discretization scheme that is advantageous in obtaining highly accurate solutions. However, the resulting systems from compact schemes are tridiagonal systems that are difficult to solve efficiently on parallel computers. Considering the almost symmetric Toeplitz structure, a parallel algorithm, simple parallel prefix (SPP), is proposed. The SPP algorithm requires less memory than the conventional LU decomposition and is efficient on parallel machines. It consists of a...

Topics: NASA Technical Reports Server (NTRS), ALGORITHMS, PARALLEL COMPUTERS, DECOMPOSITION, SIMD...

Programming languages, computer graphics, neural networks, massively parallel computers, SIMD architecture, algorithms, digital terrain models, sort computation, simulation of charged particle transport on the massively parallel processor and image processing are among the topics discussed.

Topics: NASA Technical Reports Server (NTRS), CONFERENCES, MIMD (COMPUTERS), PARALLEL PROCESSING...

In the design of parallel computers, there exists a tradeoff between the number and power of individual processors. The single instruction stream, multiple data stream (SIMD) model of parallel computers lies at one extreme of the resulting spectrum. The available hardware resources are devoted to creating the largest possible number of processors, and consequently each individual processor must use the fewest possible resources. Disagreement exists as to whether SIMD processors should be able...

Topics: NASA Technical Reports Server (NTRS), ADDRESSING, COMPUTER DESIGN, PARALLEL PROCESSING (COMPUTERS),...

This paper reports on the performance of five parallel algorithms for simulating a fully associative cache operating under the LRU (Least-Recently-Used) replacement policy. Three of the algorithms are SIMD, and are implemented on the MasPar MP-2 architecture. Two other algorithms are parallelizations of an efficient serial algorithm on the Intel Paragon. One SIMD algorithm is quite simple, but its cost is linear in the cache size. The two other SIMD algorithm are more complex, but have costs...

Topics: NASA Technical Reports Server (NTRS), ALGORITHMS, COMPUTERIZED SIMULATION, MASSIVELY PARALLEL...

We study a routing problem that arises on SIMD parallel architectures whose communication network forms a toroidal mesh. We assume there exists a set of k message descriptors (xi, yi), where (xi, yi) indicates that the ith message's recipient is offset from its sender by xi hops in one mesh dimension, and yi hops in the other. Every processor has k messages to send, and all processors use the same set of message routing descriptors. The SIMD constraint implies that at any routing step, every...

Topics: NASA Technical Reports Server (NTRS), ARCHITECTURE (COMPUTERS), COMMUNICATION NETWORKS, COMPUTER...

Massively Parallel Processor (MPP) Parallel FORTH is a derivative of FORTH-83 and Unified Software Systems' Uni-FORTH. The extension of FORTH into the realm of parallel processing on the MPP is described. With few exceptions, Parallel FORTH was made to follow the description of Uni-FORTH as closely as possible. Likewise, the parallel FORTH extensions were designed as philosophically similar to serial FORTH as possible. The MPP hardware characteristics, as viewed by the FORTH programmer, is...

Topics: NASA Technical Reports Server (NTRS), COMPUTER SYSTEMS PERFORMANCE, MASSIVELY PARALLEL PROCESSORS,...

The issue of solving the time-dependent incompressible Navier-Stokes equations on the Connection Machine 2 is addressed, for the problem of transition to turbulence of the steady flow in a channel. The spectral algorithm used serially requires O(N(4)) operations when solving the equations on an N x N x N grid; using the massive parallelism of the CM, it becomes an O(N(2)) problem. Preliminary timings of the code, written in LISP, are included and compared with a corresponding code optimized for...

Topics: NASA Technical Reports Server (NTRS), CHANNEL FLOW, INCOMPRESSIBLE FLOW, NAVIER-STOKES EQUATION,...

Unstructured grids lead to unstructured communication on distributed memory parallel computers, a problem that has been considered difficult. Here, we consider adaptive, offline communication routing for a SIMD processor grid. Our approach is empirical. We use large data sets drawn from supercomputing applications instead of an analytic model of communication load. The chief contribution of this paper is an experimental demonstration of the effectiveness of certain routing heuristics. Our...

Topics: NASA Technical Reports Server (NTRS), ARCHITECTURE (COMPUTERS), COMPUTATIONAL GRIDS, HEURISTIC...

A computational structural/material analysis and design tool which would meet industry's future demand for expedience and reduced cost is presented. This unique software 'GENOA' is dedicated to parallel and high speed analysis to perform probabilistic evaluation of high temperature composite response of aerospace systems. The development is based on detailed integration and modification of diverse fields of specialized analysis techniques and mathematical models to combine their latest...

Topics: NASA Technical Reports Server (NTRS), COMPOSITE MATERIALS, APPLICATIONS PROGRAMS (COMPUTERS),...

This is a real-time robotic controller and simulator which is a MIMD-SIMD parallel architecture for interfacing with an external host computer and providing a high degree of parallelism in computations for robotic control and simulation. It includes a host processor for receiving instructions from the external host computer and for transmitting answers to the external host computer. There are a plurality of SIMD microprocessors, each SIMD processor being a SIMD parallel processor capable of...

Topics: NASA Technical Reports Server (NTRS), ARCHITECTURE (COMPUTERS), COMPUTERIZED SIMULATION, MIMD...

We are surveying current projects in the area of parallel supercomputers. The machines considered here will become commercially available in the 1990 - 1992 time frame. All are suitable for exploring the critical issues in applying parallel processors to large scale scientific computations, in particular CFD calculations. This chapter presents an overview of the surveyed machines, and a detailed analysis of the various architectural and technology approaches taken. Particular emphasis is placed...

Topics: NASA Technical Reports Server (NTRS), ARCHITECTURE (COMPUTERS), DISTRIBUTED PROCESSING, MIMD...

Parallel programs should be machine-independent, i.e., independent of properties that are likely to differ from one parallel computer to the next. Extensions are described of Modula-2 for writing highly parallel, portable programs meeting these requirements. The extensions are: synchronous and asynchronous forms of forall statement; and control of the allocation of data to processors. Sample programs written with the extensions demonstrate the clarity of parallel programs when machine-dependent...

Topics: NASA Technical Reports Server (NTRS), ALGORITHMS, COMPUTER PROGRAMMING, COMPUTER SYSTEMS PROGRAMS,...

The continued fraction method for factoring large integers (CFRAC) was an ideal algorithm to be implemented on a massively parallel computer such as the Massively Parallel Processor (MPP). After much effort, the first 60 digit number was factored on the MPP using about 6 1/2 hours of array time. Although this result added about 10 digits to the size number that could be factored using CFRAC on a serial machine, it was already badly beaten by the implementation of Davis and Holdridge on the...

Topics: NASA Technical Reports Server (NTRS), ALGORITHMS, COMPUTER SYSTEMS PERFORMANCE, FACTORIZATION,...

A CMOS VLSI layout and verification of a 3 x 3 processor parallel computer has been completed. The layout was done using the MAGIC tool and the verification using HSPICE. Suggestions for expanding the computer into a million processor network are presented. Many problems that might be encountered when implementing a massively parallel computer are discussed.

Topics: NASA Technical Reports Server (NTRS), CMOS, SIMD (COMPUTERS), COMPUTER DESIGN, MULTIPROCESSING...

Several fine grained parallel algorithms were developed and compared to compute the Cholesky factorization of a sparse matrix. The experimental implementations are on the Connection Machine, a distributed memory SIMD machine whose programming model conceptually supplies one processor per data element. In contrast to special purpose algorithms in which the matrix structure conforms to the connection structure of the machine, the focus is on matrices with arbitrary sparsity structure. The most...

Topics: NASA Technical Reports Server (NTRS), ALGORITHMS, CHOLESKY FACTORIZATION, MATRICES (MATHEMATICS),...

A new massively parallel algorithm is presented for simulating large asymmetric circuit-switched networks, controlled by a randomized-routing policy that includes trunk-reservation. A single instruction multiple data (SIMD) implementation is described, and corresponding experiments on a 16384 processor MasPar parallel computer are reported. A multiple instruction multiple data (MIMD) implementation is also described, and corresponding experiments on an Intel IPSC/860 parallel computer, using 16...

Topics: NASA Technical Reports Server (NTRS), ALGORITHMS, CIRCUITS, MASSIVELY PARALLEL PROCESSORS, MIMD...

Highly parallel computing architectures are the only means to achieve the computation rates demanded by advanced scientific problems. A decade of research has demonstrated the feasibility of such machines and current research focuses on which architectures designated as multiple instruction multiple datastream (MIMD) and single instruction multiple datastream (SIMD) have produced the best results to date; neither shows a decisive advantage for most near-homogeneous scientific problems. For...

Topics: NASA Technical Reports Server (NTRS), COMPUTER NETWORKS, INFORMATION FLOW, MIMD (COMPUTERS), NEURAL...

Trace driven cache simulation is central to computer design. A trace is a very long sequence of reference lines from main memory. At the t(exp th) instant, reference x sub t is hashed into a set of cache locations, the contents of which are then compared with x sub t. If at the t sup th instant x sub t is not present in the cache, then it is said to be a miss, and is loaded into the cache set, possibly forcing the replacement of some other memory line, and making x sub t present for the (t+1)...

Topics: NASA Technical Reports Server (NTRS), ALGORITHMS, COMPUTER SYSTEMS DESIGN, MASSIVELY PARALLEL...

In part 1 architecture of NETRA is presented. A performance evaluation of NETRA using several common vision algorithms is also presented. Performance of algorithms when they are mapped on one cluster is described. It is shown that SIMD, MIMD, and systolic algorithms can be easily mapped onto processor clusters, and almost linear speedups are possible. For some algorithms, analytical performance results are compared with implementation performance results. It is observed that the analysis is...

Topics: NASA Technical Reports Server (NTRS), ALGORITHMS, ARCHITECTURE (COMPUTERS), COMPUTER VISION, IMAGE...

Fast, efficient parallel algorithms are presented for discrete event simulations of dynamic channel assignment schemes for wireless cellular communication networks. The driving events are call arrivals and departures, in continuous time, to cells geographically distributed across the service area. A dynamic channel assignment scheme decides which call arrivals to accept, and which channels to allocate to the accepted calls, attempting to minimize call blocking while ensuring co-channel...

Topics: NASA Technical Reports Server (NTRS), ALGORITHMS, COMMUNICATION NETWORKS, MASSIVELY PARALLEL...

A new Lagrangian formulation of the Euler equation is adopted for the calculation of 2-D supersonic steady flow. The Lagrangian formulation represents the inherent parallelism of the flow field better than the common Eulerian formulation and offers a competitive alternative on parallel computers. The implementation of the Lagrangian formulation on the Thinking Machines Corporation CM-2 Computer is described. The program uses a finite volume, first-order Godunov scheme and exhibits high accuracy...

Topics: NASA Technical Reports Server (NTRS), COMPUTATIONAL FLUID DYNAMICS, EULER EQUATIONS OF MOTION, FLOW...

An efficient unstructured 3D Euler solver is parallelized on a Thinking Machine Corporation Connection Machine 5, distributed memory computer with vectoring capability. In this paper, the single instruction multiple data (SIMD) strategy is employed through the use of the CM Fortran language and the CMSSL scientific library. The performance of the CMSSL mesh partitioner is evaluated and the overall efficiency of the parallel flow solver is discussed.

Topics: NASA Technical Reports Server (NTRS), COMPUTATIONAL FLUID DYNAMICS, COMPUTATIONAL GRIDS, CONNECTION...

Partitioning a set of N patterns in a d-dimensional metric space into K clusters - in a way that those in a given cluster are more similar to each other than the rest - is a problem of interest in astrophysics, image analysis and other fields. As there are approximately K(N)/K (factorial) possible ways of partitioning the patterns among K clusters, finding the best solution is beyond exhaustive search when N is large. Researchers show that this problem can be formulated as an optimization...

Topics: NASA Technical Reports Server (NTRS), MASSIVELY PARALLEL PROCESSORS, METRIC SPACE, NEURAL NETS,...

We present an algorithm that solves the three-dimensional Poisson equation on a cylindrical grid. The technique uses a finite-difference scheme with operator splitting. This splitting maps the banded structure of the operator matrix into a two-dimensional set of tridiagonal matrices, which are then solved in parallel. Our algorithm couples FFT techniques with the well-known ADI (Alternating Direction Implicit) method for solving Elliptic PDE's, and the implementation is extremely well suited...

Topics: NASA Technical Reports Server (NTRS), ALTERNATING DIRECTION IMPLICIT METHODS, CYLINDRICAL BODIES,...

Several years ago when INTEL and China Lake designed the ETANN chip, analog VLSI appeared to be the only way to do high density neural computing. In the last five years, however, digital parallel processing chips capable of performing neural computation functions have evolved to the point of rough equality with analog chips in system level computational density. The Naval Air Warfare Center, China Lake, has developed a real time, hardware and software system designed to implement and evaluate...

Topics: NASA Technical Reports Server (NTRS), AIRBORNE/SPACEBORNE COMPUTERS, COMPUTER VISION, HOMING...